Programmable assembly of mechanically robust and functional polymer–spore biocomposites in organic solvent

Microbial biocomposites offer genetically programmable and regenerative functionality, but their mechanical tunability remains limited by the mild conditions required for biological activity and viability. Here, we report the programmable self-assembly of Bacillus subtilis spores with benzalcyanoacetate (BCA)-functionalized polymers to form robust composites exhibiting tunable viscoelastic and tensile properties. Surface-exposed cysteines on the spore coat react with BCA motifs, forming dynamic thia-Michael networks with Young’s moduli of >100 MPa. Systematic variation of BCA reactivity and comonomer-dependent polymer dynamics enabled control over stiffness, stress-relaxation behavior, microscale morphology, and covalent biocontainment. Incorporation of engineered spores confers catalytic function that can be regenerated following solvent-triggered disassembly. This work establishes a modular platform for constructing biocomposites that are both mechanically and genetically programma..., , # Programmable assembly of mechanically robust and functional polymer–spore biocomposites in organic solvent

Dataset DOI: [10.5061/dryad.573n5tbmt](10.5061/dryad.573n5tbmt)

## Description of the data and file structure

The dataset folder contains tabular data and TIFF files that are organized into folders that correspond to each figure set found in the journal article and supporting information. For example, the folder named **Figure 1** contains data that was used to create Figure 1. Below are the background and table of contents pertaining to each dataset folder. More detailed descriptions of experimental methods can be found in the main text and supporting information.

### Files and variables

### File: Dryad.zip

#### **Folder: Figure 1**

**Description:** Data in Figure 1 were collected to investigate whether the key chemical motif benzalcyanoacetate (BCA) can covalently bind to cysteine residues on spore surface proteins. 

Fluorescent nitrobenzoxadiazole–BCA (NBD–BCA) probe...,